Pop! It's Back

Recurring "popped splints" has sidelined many older equine athletes, but a group of Kentucky surgeons may have come up with a solution.

In the vocabulary of injuries a horse might receive, "popping a splint," is considered, at most, an inconvenience which requires laying the affected horse off its normal routine. However, when it keeps happening, that little inconvenience can become a surgical problem.

The key issue surrounding what in veterinary terms is an exostosis, the "popped splint" is actually where it occurs in relation to the horse's cannon bone. The horse's splint bone is actually what is left of what was once one of its toes. The bone is still there, it just no longer reaches the ground. Therefore, it still carries weight, and as a result, all of the weight the splint bone carries is transferred to the cannon bone, which is the largest bone of the lower leg.

To paint a picture of the injury, a popped splint occurs where the splint bone lies against the cannon bone. The load (the pressure the horse is applying as it is working) that is carried from the splint bone to the cannon bone causes a tear between the attachment, causing the splint bone to tear away from the cannon bone. Calcium then builds in the affected area, sort of the body's repairing mechanism, and reattaches the splint to the cannon bone. Problem solved - if it's in the right place.

If the splint "pops" lower than normal, it's actually in a weaker position. Although the horse's body dutifully sets about repairing the area with calcium, it's in a weaker position. So, as the horse goes back to work after the lameness has subsided, the repairing calcium cracks and breaks. So you're back to square one or maybe even worse than the first time.

Sometimes the problem just keeps reoccurring each time the horse becomes sound and goes back to work, whether that be racing, chasing a calf or jumping a fence. The problem occurs in all athletic horses. However, this particular type of splint will usually occur in an older horse versus the higher splints that are so common in younger horses.

The first approach to any popped splint is always the same which is primarily rest to allow the calcium time to attach the splint to the cannon bone. Rest is often accompanied with other treatments which are directed at reducing the size of the splint blemish or speeding the re-attachment. However, a new approach as been developed by surgeons at Rood and Riddle Equine Hospital which may solve the splints that tend to reoccur.

"Instead of trying to get the splint to calcify to the cannon bone, we just took out the bottom part of the splint and the exostosis," said Larry Bramlage, DVM, an orthopedic surgeon who developed the process. "This treatment is not applicable for the usual splint where you cannot remove that much splint bone. It only applies in splints that occur in the unnecessary part of the splint bone (the bottom two-thirds)."

Bramlage and his team defined the process with their work on Thoroughbred racehorses in the racehorse-rich Lexington, Kentucky, area. However, this process could be used, if all else fails, on other athletic horses, as well.

"It's important to realize that this is basically a final effort to solve the problem," said Bramlage. "The first line of treatment should always be in providing the horse with rest and perhaps some other therapy, such as anti-inflammatory agents."

Bramlage also noted that work like this gives veterinarians concrete information with which to advise owners so all options are presented. Objective data needs to be used to determine the likelihood of a horse recovering, no matter what the treatment.

Larry Bramlage, DVM, MS, is a world-renowned equine orthopedic surgeon based at Rood and Riddle Equine Hospital in Lexington, Kentucky. He presented his findings during the 1997 AAEP Convention in Phoenix, Arizona.